It is difficult for routers to detect if traffic is a data flow suitable to be mapped to a circuit, or several sporadic packets only being better forwarded respectively. Based on the research of the characteristics of data flows, this paper introduces new concept, chain-packet, which wrap data into a chain of packets making flow detecting easy; presents a flexible and efficient switching mechanism, chain-packet switching, with which both sporadic packets and flow traffics can be forwarded across the Internet efficiently. The research results can not only improve the performance of those approaches directly based on the existing traditional packet previously, but also be propitious to QOS, traffic engineering, traffic measurements, and traffic accounts.